Wolverine Basin

CBAC January 12, 20152014-15 Observations

Name: Donny
DATE: 15-01-11
LOCATION: Crested Butte Area
ELEVATION: 9000’ to 10,400′
ASPECT: Mostly N and NE

WEATHER: Snowing all day; short periods of S3; HST 15cm; calm to light winds; temps in the upper teens to lower 20s throughout the day.

SNOWPACK/AVALANCHE OBS: No signs of instabilities or avalanches observed. New snow is light and not adding significant weight to snowpack. Looked at 12/13 interface in a couple spots and it seemed to be faceting away, although I still got rough hand sheers.

Evan’s Basion

CBAC January 11, 20152014-15 Observations

NAME: Donny
DATE: 15-01-10
ACTIVITY: Ski touring
LOCATION: Crested Butte Area
ELEVATION: 9,200 to 11,600
ASPECT: S-SE-E

WEATHER: Clear, light wind above 11,000’, warmer high than low.

SNOWPACK/AVALANCHE OBS: SH and SF, ski pen 5cm average, plenty of crusts on southern aspects. No signs of instabilities; no avalanches observed.

Washington Gulch

CBAC January 10, 20152014-15 Observations

Name: Evan Ross
DATE: 1/09/15
LOCATION: Crested Butte Area
ASPECT: E, NE
Elevation: Valley Bottom, 9,500ft
WEATHER: Sunny and warm. No wind.

SNOWPACK/AVALANCHE OBS: Low angle near Washington Gulch TH. Plenty of collapsing without any cracks. Variable slab strength with ski pen at 10cm during the good times and ski pen on the ground during the bad times. Boot pen would have been to the ground all the time. The low elevation slab has certainly been faceting out at these low elevations but the question is how much longer will it take for the slabs to become isolated? HS 60-80cm. Lots of large surface hoar in the valley. SS-N-R1-D2-O at 12,300ft on south aspect of Baldy. Likely failed around Jan 4th and originally observed on Jan 5th.

Loose snow avalanche that propagated a shallow slab 100ft wide below Gothic Spoon at 11,300ft, D2. Likely failed Jan 6th and originally observed on the 7th.

: Loose snow avalanche that propagated a shallow slab below Gothic Spoon at 11,300ft, D2. Likely failed Jan 6th and originally observed on the 7th

: SS-N-R1-D2-O at 12,300ft on south aspect of Baldy. Likely failed around Jan 4th and originally observed on Jan 5th

Skier triggered avalanche in Wolverine Basin

CBAC January 8, 20152014-15 Observations

DATE: 01/07/2015

LOCATION: Wolverine Basin

ELEVATION: 9000′ – 10,200′

ASPECT: N-E

WEATHER: Clear skies and hot in the sun. Temps below freezing in the shade. Calm to light winds.

SNOWPACK/AVALANCHE OBS: Thin crusts on SE-W aspects in the valley bottom. Surface hoar was also noted in the valley bottom. While ascending the gunsight road HS remained consistent around 110cm. Outside of the skintrack no instabilities were noted, and boot pen was essentially to the ground. Hand pits consistently showed an extremely weak snowpack with no layer greater than fist hardness. One human triggered slab avalanche occurred on a NE aspect at ~10,200′. The run was a short path (~300′) between two switchbacks on the Gunsight road visible when you enter Wolverine Basin. Near the start zone HS was approximately 75cm with consistently weak snow to the ground. As I continued down the slope I felt the snow become increasingly more supportive and near the bottom felt a collapse. The slab was triggered from approximately 250ft below the crown, and the crown depth was ~75cm. The crown was approximately 150ft wide and I would classify the slide a R2-D1. Skier 1 was on the road above the path when the avalanche occurred, and skier 2 was clear of the runout by the time the avalanche accelerated.

Windslabs near Pittsburg

CBAC January 8, 20152014-15 Observations

GUIDE(S): Jeff

DATE: 2015/01/05

ACTIVITY: Ski tour

LOCATION: Commando Trees

ELEVATION: 9600′ – 10,400

ASPECT: NW-N-NE

WEATHER: Variable/Overcast, flat light, dry most of the day, Strong to Extreme, mostly N channeled down valley

SNOWPACK/AVALANCHE OBS: sled parking (valley floor along stream) got avalanched by a D1 windslab 30cm thick that formed while we were touring! Fairly recent slab D1.5 under the cliff band of Schuykill peak above pittsburgh rollers. Schuykill looks stripped in many places & very thin, highly variable. No other signs of instability on surrounding alpine peaks

In Old Growth timber: consistent & stable pack of ~120-135cm of well bonded snow.
Bonding Tests:
Location: NW, large living room sized opening in forest @ 10,400. Lots of tree bombs evident in the pit. 25 degree slope, ski pen 10-15cm. boot pen 30cm. Progressive hardness downwards except a 1 hardness change @ 70cm down on rounds/rounding facets interface

DTH on ground (moist, dense (4F) cohesive facets, sticking to leaves, non repeatable)
DTN
CTH @ 70cm down on rounded slab (1F) & rounding facets interface (4F), Q2 (RP)
CTN
ETCX

Skied slpoes up to 50 degrees with no instabilities

1/2/15 White Rock Mountain Field Day

CBAC January 7, 2015Videos

CBAC forecaster Ian Havlick investigates snow structure in eastern forecast area outside Crested Butte

Gothic Area

CBAC January 6, 20152014-15 Observations

Guides(s): Jeff
Date: 20150104
Level One Avy Course, Tour Day
Location: East River Valley/Gothic
Elevation: 9400′ – 10,000
Aspect: SW-N-ENE

Weather: Variable/Overcast, flat light, dry most of the day, a few flurries. Winds light to strong, mostly N channeled down valley.

Snowpack/Avalanche Obs: Approximately 12 recent avalanches along Snodgrass seen from the Gothic road. Looked like skier triggered within the PWL. ~5 D1.5’s (small but going into gulley terrain traps where the debris piled up deeply) ~7 X D2’s. At the far end of Gothic Mtn (across the bridge) we remotely triggered a D1.5 from ~50m away on a 25* slope. the whole slope cracked & the pocket went within the PWL of very large facets. looked like 33-35* slope angle from 50m.

Overall, snowpack is shallow & week 50-100cm.

We got collapses & shooting cracks on a SW (240*) slope BTL @15* (guessing the crust wasn’t strong enough in a semi shaded low < slope).

Ditto on W, E, ENE (Pit collapsed before we dug it on the approach!)

Probably 10 collapses in all spanning large distances.

ENE pit: The structure is >5mm Facets w/ soft (often 4F slab over the top).

WSW pit: (10 m away from above pit) 25* slope, knife hard 6cm crust over facets with perc. columns in the facets showed no propagation and only Q2/Q3 failures within the top layers resting on crust.

Snodgrass

CBAC January 6, 20152014-15 Observations

Guide(s): JSJ
Date: 20150105
Activity: BC Ski
Location: Snodgrass
Elevation:9400′ – 10,000
Aspect: E/SE

Weather: Broken to scattered clouds. 3cm new snow. Moderate and sustained winds from West and North (down valley funnel) most of day.

Snowpack/Avalanche Obs: Same as previous post from yesterday in same zone. Got a few collapses and shooting cracks on 25 degree slopes on an East aspect. Ski pen at times was full depth. Downvalley N winds were transporting new low density snow and re-filling the skin track between laps.

Irwin Tenure

CBAC January 6, 20152014-15 Observations

Recent Observations: (Surface, structure, cracking, collapsing, PWLs, Ski Pen)

Wind stripped snow in higher terrain exposing old tracks on west terrain even in mid to lower westwall. Looked like straight west Winds. Small isolated wind slabs up to 1F hardness. Snow remained dry, no solar radiation.

East: Paperboy Route w/ ski cuts, no explosives. Fresh Wind slabs developed very touchy with ski cut triggering wind slab in Swill & Bender. Swill SS-ASc-R1-D1-I. 100’ wide 10-20” deep, ran 500’ through choke. Candy’s & Sonic also triggered but smaller 6” deep, ran short of Choke. Wind slab less developed past pre-evac.

South: Small 4” windslabs in Sunny Shoulder barely running. Cocktail Bowl Skiing very well!

West: Sunset L&R a little wind effected but good, small windslab from a ski cut on round two. 8-12” deep 30’ wide, ran 40’.

Upper Upper: Isolated windslabs in lower UUWW. Not UUWW proper. Very shallow windslabs 1F pulling out and stubbornly running short distances from airblasts. Significant scouring, probably lost 1-3f feet of snow depth from terrain. Probably one reason for no results, decreasing load!

Kebler Pass Area

CBAC January 4, 20152014-15 Observations

Location: Irwin Cat Ski

GENERAL COMMENTS: Snow began in the early am and by 9:30 snow began in earnest with strong winds near and above treeline, but even still filtering into below treeline areas. Windslabs were very touchy and growing in size 10”+ in E. Barkmarker by the afternoon. Poor visibility prevented backcountry obs. Storm really fired up around 1500, with that classic Irwin NW-flow nukage that was continuing as we left for the day.

East: am: Perfect loading speeds and direction for EBM. Cracks shooting 20-40’. Fresh windslabs 6-10” deep. Remotely triggered Bender from Swill and got Candy’s to clean out wall to wall while approaching the cornice mid day. D-.5 -1.

South: Sunny Shoulder had stout crust (3-5 cm), (Jan 3 interface) with only 1-2” of new snow on top in the am. New snow seems to be bonding OK with minimal sluffing.

West: UWW, Moonrise, Far Out, Sunset, feeling slabby but not yet slabbed up across extensive terrain. Classic 6-10” windslabs on little rolls behind tree islands, but not long running, or widely propagating… yet. Round two Below Moonrise two small pockets 6-8” deep 20’ wide not really running. Did seem that the new wind and snow was touchy in areas holding yesterdays SH/MFcr combo….worth watching.

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